Surveillance networks (such as CCTV networks) are widely deployed in sophisticated monitoring systems. Prominent applications for electronic surveillance include asset security, congestion management and operational monitoring. Conventional surveillance networks produce a series of surveillance streams that are usually relayed to a control room for evaluation by an operator (such as a security guard or process facility manager).
Most surveillance systems temporarily preserve surveillance content in storage mediums (such as magnetic hard drives and solid state memory) to facilitate subsequent evaluation by an authorized reviewer (such as a manager or police officer). The surveillance content may be encoded and compressed (typically using an established encoding protocol such as MPEG for video streams) prior to storage to reduce memory overheads. Surveillance content is often periodically overwritten during cyclic reuse of the allotted storage mediums (although some organization may prescribe minimum retention periods for sensitive surveillance content).